Topic: Mystery copper lines

When my 1972 Taylor-built Contessa was re-engined about 20 years ago with a Yanmar 1GM10, the previous owner cut -- but didn't remove -- a pair of copper lines that apparently connected the old engine to the exhaust thru-hull. Can anyone tell me what purpose these lines served? They are about 1/4 inch in diameter and run along the port-side of the engine compartment back to the exhaust manifold on the transom thru-hull. Thanks.

Re: Mystery copper lines

Probably bonding wires. Grounding the engine to the thru-hulls and maybe to anodes. google boat bonding and grounding.

Re: Mystery copper lines

Re: Mystery copper lines

Not so.  If setup is the same as I have on my 1976 Contessa with the Petter engine, the cooling system had two injection points -- one close to the engine and one at the top of the gooseneck in the transom.  The copper lines were the connection. 

Since you have repowered and are not using these lines you may just cap and remove them.